Consider the body’s daily rhythm. The hormone melatonin, produced by the pineal gland, is virtually undetectable during the day. As night falls, it begins to increase, and its levels peak in the early morning hours. Cortisol levels also rise in the early morning hours and spike just before we awaken. Growth hormone is secreted mostly in deep sleep and is usually undetectable during the day. Thyroid-stimulating hormone peaks in early morning. The periodic release of all these hormones is essential in preventing resistance.
